I hardly ever use prototypes. Why? Because I mainly program with modules and objects. And prototypes are useless with method calls, as the subroutine handling the method call is determined at run-time. And prototype checks occur at compile time. So if you're into OO programming, don't worry about prototypes (at least not in Perl 5 ;-)

The only use I've had for a prototype in my career, was with the share() subroutine in my forks module. That subroutine should be passed a single scalar, array or hash, but receive the appropriate reference as the parameter (without flattening). Take this example: 

sub foo (\[$@%]) { print "received a $_[0]\n" }

foo( $a );
foo( @a );
foo( %a );

[download]
will print something like: 
received a SCALAR(0x107c84)
received a ARRAY(0x107d44)
received a HASH(0x107d68)
Without the prototype this wouldn't work at all. I guess this was one of the neat features added in 5.8.0.

On the other hand, I know of people who use prototypes on subroutines that are intended to be called as methods purely for the documentational value.

Hope this helps.

Liz

In reply to Re: Prototyping Subs: Good,Bad,Indifferent by liz
in thread Prototyping Subs: Good,Bad,Indifferent by knexus

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.